NONMEM Users Network Archive

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RE: NM7 Question on METHOD=IMP

From: Bauer, Robert <Robert.Bauer>
Date: Fri, 30 Oct 2009 11:31:35 -0400

Dear Thuy:
The OBJ of the IOV model is clearly incorrect. You may want to inspect
several things:
1) Is the IOV modeled and mu referenced in a similar manner as the
example 7 in the intro7.pdf manual
2) Based on your GRD setting, it appears that your original, non-IOV
code has Thetas 10 and 11 as sigma-like parameters. Is this still the
case with the new IOV control stream

Robert J. Bauer, Ph.D.
Vice President, Pharmacometrics
ICON Development Solutions

Tel: (215) 616-6428
Mob: (925) 286-0769
Email: Robert.Bauer
Web: www.icondevsolutions.com

 

 

 


________________________________

From: owner-nmusers
On Behalf Of Vu, Thuy
Sent: Thursday, October 29, 2009 7:12 PM
To: nmusers
Subject: [NMusers] NM7 Question on METHOD=IMP


Dear NM7 users,
 
According to the examples in the users guide, the IMP step followed the
SAEM step with EONLY=1 to evaluate the objective function. In all of =
my
models (for the same data set), I have these two $EST steps:
$EST METHOD=SAEM INTER FILE=saem.txt NBURN=3000 NITER=2000 =
PRINT=5

CTYPE=3 GRD=DDDDDDDDDSSDDD SEED=20091013 ISAMPLE=2
$EST METHOD=IMP EONLY=1 FILE=imp.txt NITER=300 ISAMPLE=3000 =
PRINT=1
 
In my base model, the OBJ trend in the IMP step is as follows (truncated
here):
iteration 296 OBJ= -1796.0722480934633
iteration 297 OBJ= -1802.1845380634943
iteration 298 OBJ= -1795.4946269639131
iteration 299 OBJ= -1795.8286754523187
Elapsed estimation time in seconds: 230513
iteration 300 OBJ= -1791.4880075805286
 
When I add IOV on one of the parameters (to the base model), I got the
following trend, which showed the OBJ became worse:
iteration 296 OBJ= 52215.178158178285
iteration 297 OBJ= 51758.149614882743
iteration 298 OBJ= 51850.531967877905
iteration 299 OBJ= 53377.558672094958
Elapsed estimation time in seconds: 314605
iteration 300 OBJ= 53030.267320528052
 
When I compared the GOF plots and parameter estimates for these two
models, they looked pretty much the same. I could not find any obvious
differences between them. How would I interpret/compare the OBJ for
these 2 models? What could be the reasons for such difference in the OBJ
for the 2 models?
 
Thank you in advance for your help,
-Thuy
 
 
 

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Received on Fri Oct 30 2009 - 11:31:35 EDT

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